Antheraea proylei J. sericin induces apoptosis in a caspase dependent manner in A549 and HeLa cells and caspase independent manner in PC3 cells

Abstract BackgroundIn spite of much progress in understanding the biology of cancer disease, advancement in technology for early diagnosis, the expanding array of anticancer drugs and treatment modalities, the global cancer burden is still significant and increasing. It is estimated that the new cases of cancer in the year 2040 will be 29.4 million per year globally. Sericin, an adhesive protein of silk cocoons has been shown to be a potential protein in various biomedical applications including cancer therapeutics. The present study evaluates the anticancer property of sericin from cocoons of Antheraea proylei J. (SAP) against human lung cancer (A549), cervical cancer (HeLa), and prostate cancer (PC3) cell lines. This is the first report of anti-cancer activity of the non-mulberry silkworm A. proylei J. Methods SAP was prepared from cocoons of A. proylei J. by the process of degumming method. The amino acid composition of SAP was determined by HPLC. Cytotoxicity activity was assessed by MTT assay and genotoxicity activity was assessed by comet assay. Cleavage of caspase and PARP proteins and phosphorylation of MAPK pathway members were analysed by Western blotting. Cell cycle analysis was done by flow cytometery.ResultsSAP causes cytotoxicity to A549, HeLa and PC3 cell lines with the IC50 values ranging from 3.4-3.9 µg/µl. SAP induces apoptosis in a dose-dependent manner through caspase-3 and p38 and ERK pathways in A549 and HeLa cells respectively whereas in PC3 cells, SAP induces apoptosis independent of caspase through p38 pathway. Moreover, in the case of A549 and HeLa cells SAP induces cell cycle arrest at S phase in a dose dependent manner whereas at G0 phase in the case PC3 cells.ConclusionSAP induces apoptosis in A549, HeLa, and PC3. The difference in the molecular mechanisms of apoptosis induced by SAP in A549 and HeLa and in PC3 may be due to the differences in the genotypes of the cancer cell lines. However, further investigation is warranted. The overall results of the present study envisage the possibility of using SAP as anti-tumorigenic agent.